Reading and Listening have a fixed answer key. Writing and Speaking do not — they're marked against detailed criteria by a trained examiner. Understanding the difference explains why a confident guess and a real score can land in different places.
IELTS is really two different kinds of test bundled into one exam. Reading and Listening are objectively marked: your raw score (how many of 40 questions you got right) converts to a band using a fixed conversion table. Writing and Speaking are subjectively marked by a trained, certified examiner against detailed public band descriptors — there is no single "correct" essay or answer, only a range of criteria your response is judged against.
Both are marked out of 40 questions. Your raw score converts to a band using a conversion table — roughly, higher raw scores map to higher bands, but the exact cutoffs shift slightly between test versions to keep difficulty consistent across sittings. This means "37/40" isn't always exactly the same band on every test, though it's usually close.
Every Writing task is marked against four criteria, each worth 25% of the task score: Task Achievement (Task 1) or Task Response (Task 2) — did you actually answer what was asked; Coherence and Cohesion — is it logically organised and easy to follow; Lexical Resource — range and accuracy of vocabulary; and Grammatical Range and Accuracy — variety and correctness of sentence structures. Task 2 counts for twice as much as Task 1 toward your overall Writing band.
Speaking uses its own four criteria of equal weight: Fluency and Coherence, Lexical Resource, Grammatical Range and Accuracy, and Pronunciation. It is conducted as a face-to-face or video interview in three parts — general questions, a two-minute individual long turn on a given topic, then a follow-up discussion — and marked live by the examiner conducting it.
A teacher reading an essay once, without formally scoring it against all four criteria side by side, is doing something genuinely harder than it looks — trained examiners go through certification specifically because consistent marking against detailed public descriptors is a skill, not just familiarity with English. A fluent-sounding essay can hide a Task Response problem a quick read misses; a slightly awkward one can still hit every criterion a teacher skims past. This is exactly the gap structured, criteria-based feedback (human or AI) is built to close.
One free essay check shows you exactly how AI feedback breaks a response down by criterion — no card required.